Question: In the right triangle shown, $BC = 5$ and $AB = 10$. What is $AC$ ? A C B ? 5 10
Answer: We know $a^2 + b^2 = c^2$ We want to find $b$ ; let $a = 5$ and $c = 10$ So $b^2 = c^2 - a^2 = 10^2 - 5^2 = 75$ Then, $b = \sqrt{75}$ Simplifying the radical gives $b = 5\sqrt{3}.$